Human milk contains a diverse and abundant set of neutral and acidic oligosaccharides (human milk oligosaccharides, HMOS). Many of these molecules are not utilized directly by infants for nutrition, but they nevertheless serve critical roles in the establishment of a healthy gut microbiome, in the prevention of disease, and in immune function. Prior to the invention described herein, the ability to produce HMOS inexpensively at large scale was problematic. For example, HMOS production through chemical synthesis was limited by stereo-specificity issues, precursor availability, product impurities, and high overall cost. As such, there is a pressing need for new strategies to inexpensively manufacture large quantities of HMOS for a variety of commercial applications.